Loader linkage

ABSTRACT

The bucket control linkage of a tractor loader includes a vertically disposed lever pivotally connected intermediate its upper and lower ends to a boom. A dump link is interconnected between the lower end of the lever and the upper rear of the bucket. The bucket control linkage also includes a bucket operating jack having its front rod end pivotally connected to the upper end of the lever and its rear cylinder end pivotally connected to a special linkage. The special linkage includes a pair of pivotally interconnected links, one of which is pivotally connected to the boom and the other of which is pivotally connected to the tractor frame at a point spaced forwardly of the pivot connection between the boom and the frame. The special linkage to which the cylinder end of the bucket operating jack is connected, causes the bucket to automatically retract as the boom is raised through an initial angle toward its level position and then will cause the bucket to pivot forwardly relative to the boom to maintain the bucket in a proper material retaining altitude in relation to the ground. The various components of the bucket operating linkage are in line with the longitudinal vertical plane of the boom for ideal component stress distribution. The bucket is retracted by introduction of hydraulic fluid to the cylinder end of the dumping jack whereby the greatest possible breakout force is achieved by the jack. The rod end of the hydraulic jack is pressurized to dump the bucket thus giving the shortest possible dumping time. The connections between the bucket operating linkage and the frame of the tractor are relatively low thereby affording good operator visibility and desirable loader frame stress distribution.

United States Patent [191 Crum et al.

[451 Jan. 22, 1974 LOADER LINKAGE [75] Inventors: Robert L. Crum;Ishwarlal P. Patel,

both of Springfield, Ill.

[73] Assignee: Allis-Chalmers Corporation,

Milwaukee, Wis.

[22] Filed: Nov. 16, 1972 [21] Appl. No.: 307,054

[52] US. Cl. 214/776, 214/778 [51] Int. Cl E02f 3/00 [58] Field ofSearch 214/776, 775, 773, 769

[56] References Cited UNITED STATES PATENTS 9/1969 Campbell 214/77610/1965 Mclndoo 214/776 Primary Examiner-Gerald M. Forlenza AssistantExaminer-John Mannix Attorney, Agent, or Firm-Charles L. Schwab; RobertB. Benson; Kenneth C. McKivett 5 7 ABSTRACT control linkage alsoincludes a bucket operating jack having its front rod end pivotallyconnected to the upper end of the lever and its rear cylinder endpivotally connected to a special linkage. The special linkage includes apair of pivotally interconnected links, one of which is pivotallyconnected to the boom and the other of which is pivotally connected tothe tractor frame at a point spaced forwardly of the pivot connectionbetween the boom and the frame. The special linkage to which thecylinder end of the bucket operating jack is connected, causes thebucket to automatically retract as the boom is raised through an initialangle toward its level position and then will cause the bucket to pivotforwardly relative to the boom to maintain the bucket in a propermaterial retaining altitude in relation to the ground. The variouscomponents of the bucket operating linkage are in line with thelongitudinal vertical plane of the boom for ideal component stressdistribution. The bucket is retracted by introduction of hydraulic fluidto the cylinder end of the dumping jack whereby the greatest possiblebreakout force is achieved by the jack. The rod end of the hydraulicjack is pressurized to dump the bucket thus giving the shortest possibledumping time. The connections between the bucket operating linkage andthe frame of the tractor are relatively low thereby affording goodoperator visibility and desirable loader frame stress distribution.

10 Claims, 3 Drawing Figures PATENTED JAN 22 I974 SHEET 10F 2 PATENTEBJAN 2 21974 SHEET20F2 LOADER LINKAGE BACKGROUND OF THE INVENTIONl-leretofore others have suggested various linkages for tractor loaders.There are a number of prior art linkages shown in US. Pat. Nos.2,846,097; 2,645,369; 3,057,496; 2,799,412; 3,389,820; 2,986,l66;3,598,267; 3,224,607; 2,711,257 and Re 24,746.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides aloader linkage which achieves a number of desirable objectives, thesebeing:

1. The bucket dumping cylinders are positioned so that the closed end ofthe cylinder is pressurized to retract the bucket thereby providing thegreatest possible breakout force for loading the bucket, and the rod endof the cylinder is pressurized to dump the bucket thereby providing thefastest possible dumping;

2. A unique linkage is utilized to mount the cylinder end of the dumpjack whereby the bucket will automatically pivot on the boom to maintaina relatively level position so that the operator does not have tooperate the bucket control valve as the boom is raised. Also, a dirtbank can be scraped by the bucket with greater ease and the center ofgravity of the bucket load with the bucket fully retracted is relativelyclose to the tractor thereby aiding in unit stability;

3. The bucket tilt linkage consists of in line components therebyproviding the most desirable component stress distribution; and

4. The linkage by which the bucket operating jack is connected to theframe is relatively low thereby providing good operator visibility andminimizing tractor frame stress problems.

BRIEF DESCRIPTION OF THE DRAWINGS One embodiment of the presentinvention is illustrated in the attached two sheets of patent drawingsin which:

FIG. 1 is a side view of a tractor loader incorporating the presentinvention;

FIG. 2 is a top view of the loader linkage shown in FIG. 1 with partsbroken away for illustration purposes and FIG. 3 is a side view of thetractor loader shown in FIG. 1 wherein the loader linkage has beenraised to an elevated position.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIGS. 1 and 2 of thedrawings, the loader linkage of the present invention is mounted on acrawler tractor 11 having a frame 12 which includes an upstandingsupport 13 at each lateral side of the tractor. The tractor 11 issupported on and propelled by an endless track running gear 14 ofconventional construction. The loader linkage includes a boom 16pivotally mounted at its rear end to the support 13 of the tractor frame12 by a transverse pivot pin 17 on a transverse axis 18. A bucket 19 ispivotally connected at its lower rear portion to the front end of theboom 16 by a pivot pin 21 on a transverse axis 22. Raising and loweringof the boom is achieved by operation of a double acting hydraulic jack23 having its rod end pivotally connected to a downwardly depending part24 of the boom 16 by a transverse pivot pin 26. The cylinder 27 of thejack 23 is secured to the frame 12 by a trunnion 28 on a transversepivot axis 19. A lever structure 31 is connected intermediate itsopposite ends to an upstanding part 32 on the boom 16 by a pivot pin 33for pivotal movement about a transverse axis 34. The lever structure 31includes a pair of levers 36, 37. The upper ends of the levers 36, 37are pivotally connected to a rod 38 of an expansible and contractiblestrut in the form of a double acting hydraulic jack 39 by a transversepin 41. The opposite ends of the levers 36, 37, disposed at oppositesides of the boom 16, are pivotally connected to a pair of dump links42, 43 by pivot pins 44, 46 respectively. The corresponding forward endsof the dump links 42, 43 are pivotally connected to the upper rearportion of the bucket 19 by a transverse pivot pin 47. The cylinder 51of the jack 39 is pivotally connected to the upper ends of connectinglinks 52, 57 and reversing links 53, 58 by a transverse pivot pin 54 forswinging movement about a common transverse axis 56. The bottom ends oflinks 52 and 57 are pivotally connected to the boom 16 by a transversepivot pin 61 on a transverse pivot axis 62. The rear ends of reversinglinks 53, 58 are pivotally connected to the support 13 by a pair oftransverse pins 66, 67 which are aligned on a transverse axis 68disposed forwardly and above the transverse axis 18 on which the boom 16is mounted on the frame 12 of the tractor.

Although a single linkage for the near side of the tractor has beenillustrated and described it should be understood that a duplicatelinkage is provided on the opposite side of the tractor.

As shown in FIG. 1 the bucket 19 has been loaded with material and thebucket rolled back on its axis 22 to a position preparatory to raisingthe bucket. In FIG. 3 the bucket 19 has been elevated by extension ofthe lift jack 23 and consequent swinging movement of the boom 16 to theposition shown. The bucket dumping jack 39 has not been actuated;however, it will be noted that the bucket control linkage comprising theconnecting links 52, 57 and reversing links 53, 58 have swung the jackpivot axis 56 rearwardly to automatically pivot the bucket 19counterclockwise about its axis 22 as the boom 16 is raised. As the boom16 is raised toward an approximate horizontal position the links 52, 57,53, 58 will cause the bucket to swing substantially in unison with theboom. As the boom, in its upward swing, approaches a horizontal positionthe bucket control linkage, that is links 52, 57, 53, 58 will begin topivot the bucket counterclockwise so as to keep the bucket in itsillustrated material retaining position. The bucket control linkagecontinues to force the bucket counterclockwise relative to the boom asthe boom is swung to its raised position shown in FIG. 3.

The illustrated linkage causes the bucket to scrape the dirt bank withgreater ease and keeps the center of gravity as close as possible to thetractor during initial upward movement of the boom. By placing theloader linkage components in line, that is in a vertical longitudinalplane, the component stresses are minimized and the most effectiveapplication of hydraulic jack forces is achieved. The linkage has arelatively low silhouette thus facilitating operator visibility andminimizing tractor frame stress problems.

In loader design it is desirable to keep hydraulic hoses short. Thus itis desirable to connect the cylinder component of the jack to thetractor, rather than the rod end. This goal is achieved in the presentdesign. In

addition, by using the expansion of the jack 39 to achieve roll back ofthe bucket, the greatest force available from the jack 39 is used tobreak out the load. This of course is a desirable parameter of loaderdesign. it is also desired to keep dumping time to a minimum. This isachieved by using contraction of the jack 39 to achieve dumping of thebucket 19. The various features of the present invention contribute to aloader having desirable loading and handling characteristics. At thesame time the novel loader linkage of this invention is comprised ofcomponents which are relatively easy and inexpensive to manufacture,thus providing the user with the advantages of an efficient tool at areasonable cost.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. in a tractor loader having a frame, the combination comprising:

a longitudinally extending boom pivotally connected to said frame on afirst transverse axis, a bucket pivotallyconnected at its lower rearportion to the front end of said boom on a second transverse axis, alift jack operatively interposed between said frame and said boom, alever structure pivotally connected intermediate its upper and lowerends to an intermediate part of said boom on a third transverse axis, adump link structure pivotally connected at one of its opposite ends tothe upper rear portion of said bucket and pivotally connected at theother of its opposite ends to said lower end of said lever structure, anexpansible and contractible strut pivotally connected at one of itsopposite ends to said upper end of said lever structure, and linkagemeans interconnecting said strut, frame and boom including a first linkpivotally connected at one of its opposite ends to said boom on a fourthtransverse axis disposed forwardly of said first transverse axis,

a second link pivotally connected at one of its opposite ends to saidframe on a fifth transverse axis disposed forwardly of said firsttransverse axis,

first pivot means pivotally interconnecting said first and second linkson a transverse axis spaced from said fourth and fifth axes, and

second pivot means pivotally connecting the other end of said strut toone of said first and second links on a transverse axis spaced from saidfourth and fifth axes whereby said strut is in overlying relation tosaid boom.

2. The invention of claim 1 wherein the transverse axis interconnectingsaid first and second links is the same transverse axis on which saidstrut and said one of said links are pivotally connected.

3. The invention of claim 2 wherein said first and second pivot meanscomprise a transverse pivot pin.

4. The invention of claim 1 wherein said fifth pivot axis is spacedabove said first pivot axis.

5. The invention of claim 4 wherein the transverse axis interconnectingsaid first and second links is the same transverse axis on which saidstrut and said one of said links are pivotally connected.

6. The invention of claim 1 wherein said strut lies in the longitudinalvertical plane of said boom.

7. The invention of claim 6 wherein said lever structure includes leverson transversely opposite sides of said boom pivotally connected to thelatter on said third axis and wherein said dump link structure includesdump links on transversely opposite sides of said boom having theircorresponding opposite ends pivotally connected to said bucket andlevers.

8. The invention of claim 6 wherein said linkage means includes a pairof first links on opposite transverse sides of said boom pivotallyconnected to said boom on said fourth axis,

a pair of second links disposed on the transversely outer sides of saidfirst links and pivotally connected to said frame on said fifth axis,

said first pivot means pivotally interconnects said pairs of links, and

said second pivot means pivotally connects the other end of said strutto one of said pairs of first and second links. 1

9. The invention of claim 8 wherein said first and second pivot meanscomprise a transverse pivot pin.

10. The invention of claim 1 wherein said strut includes a double actinghydraulic jack having its rod end pivotally connected to said upper endof said lever structure and having its cylinder end pivotally connectedby said second pivot means to one of said first and second links.

1. In a tractor loader having a frame, the combination comprising: alongitudinally extending boom pivotally connected to said frame on afirst transverse axis, a bucket pivotally connected at its lower rearportion to the front end of said boom on a second transverse axis, alift jack operatively interposed between said frame and said boom, alever structure pivotally connected intermediate its upper and lowerends to an intermediate part of said boom on a third transverse axis, adump link structure pivotally connected at one of its opposite ends tothe upper rear portion of said bucket and pivotally connected at theother of its opposite ends to said lower end of said lever structure, anexpansible and contractible strut pivotally connected at one of itsopposite ends to said upper end of said lever structure, and linkagemeans interconnecting said strut, frame and boom including a first linkpivotally connected at one of its opposite ends to said boom on a fourthtransverse axis disposed forwardly of said first transverse axis, asecond link pivotally connected at one of its opposite ends to saidframe on a fifth transverse axis disposed forwardly of said firsttransverse axis, first pivot means pivotally interconnecting said firstand second links on a transverse axis spaced from said fourth and fifthaxes, and second pivot means pivotally connecting the other end of saidstrut to one of said first and second links on a transverse axis spacedfrom said fourth and fifth axes whereby said strut is in overlyingrelation to said boom.
 2. The invention of claim 1 wherein thetransverse axis interconnecting said first and second links is the sametransverse axis on which said strut and said one of said links arepivotally connected.
 3. The invention of claim 2 wherein said first andsecond pivot means comprise a transverse pivot pin.
 4. The invention ofclaim 1 wherein said fifth pivot axis is spaced above said first pivotaxis.
 5. The invention of claim 4 wherein the transverse axisinterconnecting said first and second links is the same transverse axison which said strut and said one of said links are pivotally connected.6. The invention of claim 1 wherein said strut lies in the longitudinalvertical plane of said boom.
 7. The invEntion of claim 6 wherein saidlever structure includes levers on transversely opposite sides of saidboom pivotally connected to the latter on said third axis and whereinsaid dump link structure includes dump links on transversely oppositesides of said boom having their corresponding opposite ends pivotallyconnected to said bucket and levers.
 8. The invention of claim 6 whereinsaid linkage means includes a pair of first links on opposite transversesides of said boom pivotally connected to said boom on said fourth axis,a pair of second links disposed on the transversely outer sides of saidfirst links and pivotally connected to said frame on said fifth axis,said first pivot means pivotally interconnects said pairs of links, andsaid second pivot means pivotally connects the other end of said strutto one of said pairs of first and second links.
 9. The invention ofclaim 8 wherein said first and second pivot means comprise a transversepivot pin.
 10. The invention of claim 1 wherein said strut includes adouble acting hydraulic jack having its rod end pivotally connected tosaid upper end of said lever structure and having its cylinder endpivotally connected by said second pivot means to one of said first andsecond links.